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<span id="ALARM-_002d_002d_002d-Execute-a-routine-after-a-given-delay"></span><h3 class="section">8.13 <code>ALARM</code> &mdash; Execute a routine after a given delay</h3>
<span id="index-ALARM"></span>
<span id="index-delayed-execution"></span>

<dl compact="compact">
<dt><em>Description</em>:</dt>
<dd><p><code>ALARM(SECONDS, HANDLER [, STATUS])</code> causes external subroutine <var>HANDLER</var>
to be executed after a delay of <var>SECONDS</var> by using <code>alarm(2)</code> to
set up a signal and <code>signal(2)</code> to catch it. If <var>STATUS</var> is
supplied, it will be returned with the number of seconds remaining until
any previously scheduled alarm was due to be delivered, or zero if there
was no previously scheduled alarm.
</p>
</dd>
<dt><em>Standard</em>:</dt>
<dd><p>GNU extension
</p>
</dd>
<dt><em>Class</em>:</dt>
<dd><p>Subroutine
</p>
</dd>
<dt><em>Syntax</em>:</dt>
<dd><p><code>CALL ALARM(SECONDS, HANDLER [, STATUS])</code>
</p>
</dd>
<dt><em>Arguments</em>:</dt>
<dd><table>
<tr><td width="15%"><var>SECONDS</var></td><td width="70%">The type of the argument shall be a scalar
<code>INTEGER</code>. It is <code>INTENT(IN)</code>.</td></tr>
<tr><td width="15%"><var>HANDLER</var></td><td width="70%">Signal handler (<code>INTEGER FUNCTION</code> or
<code>SUBROUTINE</code>) or dummy/global <code>INTEGER</code> scalar. The scalar 
values may be either <code>SIG_IGN=1</code> to ignore the alarm generated 
or <code>SIG_DFL=0</code> to set the default action. It is <code>INTENT(IN)</code>.</td></tr>
<tr><td width="15%"><var>STATUS</var></td><td width="70%">(Optional) <var>STATUS</var> shall be a scalar
variable of the default <code>INTEGER</code> kind. It is <code>INTENT(OUT)</code>.</td></tr>
</table>

</dd>
<dt><em>Example</em>:</dt>
<dd><div class="example">
<pre class="example">program test_alarm
  external handler_print
  integer i
  call alarm (3, handler_print, i)
  print *, i
  call sleep(10)
end program test_alarm
</pre></div>
<p>This will cause the external routine <var>handler_print</var> to be called
after 3 seconds.
</p></dd>
</dl>






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